
\begin{tikzpicture}[scale=.8]
  \tkzDefPoints{-4/4/l11,4/4/l12,-4/0/l21,4/0/l22,-4/3/l1,4/3/l2}
  \tkzDefPoints{0/3/P}
  \tkzDrawSegments(l11,l12 l21,l22 l1,l2)
  \tkzDrawPoints(P)
  \tkzLabelSegment[left,pos=0](l11,l12){$l_1$}
  \tkzLabelSegment[left,pos=0](l21,l22){$l_2$}
  \tkzLabelSegment[left,pos=0](l1,l2){$l$}
  \tkzLabelPoints[below right](P)
\end{tikzpicture}
